Analytical performance evaluation of the Norudia HbA1c assay

Abstract

Background: Hemoglobin A_1c (HbA_1c) is arguably the most important biomarker used in the diagnosis and treatment monitoring of diabetes mellitus. We evaluated the analytical performance of the Norudia HbA_1c assay (Sekisui Medical Co., LTD), which uses an enzymatic method incorporated into a fully automated, high-throughput system.

Methods: The precision, linearity, and carryover of the Norudia HbA_1c assay were evaluated. Using 60 patient samples, comparative analysis of HbA_1c measurements with two commonly used HbA_1c assays, the D100 (Bio-Rad Laboratories, Inc) and HLC-723 G11 (Tosoh), was undergone. Thirteen commutable samples with known HbA_1c concentrations measured using an IFCC reference measurement procedure were used to compare accuracy between methods. Interference of HbA_1c measurement by Hb variants was evaluated using 16 known Hb variant samples.

Results: Repeatability (% CV) for low and high concentrations ranged from 1.12%-1.50% and 0.66%-0.75%, respectively, and within-laboratory precision for low and high concentrations ranged from 1.73%-2.89% and 0.98%-1.64%, respectively. For linearity, the coefficient of determination was 0.9987. No significant carryover was observed. When compared to the D100 and HLC-723 G11 assays, the Norudia HbA_1c assay showed the best accuracy with the lowest mean bias (-1.72%). Furthermore, the Norudia was least affected by Hb variants and gave the most reliable HbA_1c measurements.

Conclusion: The Norudia HbA_1c showed excellent analytical performance with good precision and linearity, and minimal carryover. When compared to other routine HbA_1c methods, the Norudia HbA_1c assay showed the highest accuracy and was least affected by Hb variants.

Keywords: Hb variant; Norudia HbA1c assay; accuracy; analytical performance; linearity; precision.